1. Field of the Invention
The invention relates to flood control systems and apparatus and, more particularly, to a method of using coupled piles to form a flood barrier, a system embodying the method, and apparatus for use in the method and system.
2. Description of Related Art, Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
The effect of normal compaction of alluvial soil over time is exacerbated by river levees that prevent the seasonal deposit of new sediment and by extraction of subsurface minerals, particularly oil. Coastal wetland erosion, whether due to salt-water intrusion resulting from man-made canals and waterways or to a failure to replenish wetland soils after subsidence, provides a channel or at least a shorter path for storm surges to reach inland and reduces storm-surge protection afforded by coastal wetlands, which would otherwise dissipate some of the energy of a storm surge and consequently reduce the height of the surge. Floodwalls and levees are increasingly necessary to form a barrier against rising water due to storm surges, tidal action, and high river stages. Flooding that is a consequence of the failure of a levee or floodwall, particularly during storm surges onto low-lying coastal areas that are below sea level, can be catastrophic.
In developed areas, the dislocation of existing infrastructure may be undesirable and the cost of obtaining rights-of-way may become prohibitive. In such developed areas, floodwalls are used, either in conjunction with small earthen levees or as an alternative to earthen levees.
Typically, floodwalls comprise a series of sheet metal piles that are driven into the ground with a portion of each pile projecting above the ground. Conventionally, the sheet metal piles are abutted, overlapped, or connected longitudinally to form a single-layer wall Single-layer piles obtain strength to resist transverse movement based on the depth of insertion into the soil and the horizontal resistance of the soil in which the piles are placed. Peaty and relatively noncompacted soils require piles to be inserted to substantial depths to increase the horizontal resistance of these soils. Some of the floodwall failures in New Orleans during Hurricane Katrina were the result of a combination of inadequate soil resistance and piles that were too short and were consequently driven too shallowly under the circumstances.
Increasing the protection afforded by floodwalls in existing developed areas, particularly in New Orleans and surrounding areas, requires stronger floodwalls. Given the poor soil conditions in the area, simply increasing the length of the sheet metal piles may not be allow the strength of the floodwalls to be increased to the level of protection desired. Consequently, a new method of providing floodwalls, and a new system and apparatus for floodwall protection, is desirable. Accordingly, it is an object of the present invention to provide a new and more effective method for creating floodwalls in limited areas and a new floodwall and levee system and apparatus, for use where available rights-of-way are limited, that are stronger than conventional floodwalls. It is also an object of the present invention to provide a new method and a new system and apparatus that is more cost efficient than conventional methods, systems, and apparatus. Finally, it is an object of the present invention to provide a method of reinforcing or strengthening existing, single-wall floodwalls.